Hey, I'm in the industry as well (though as an actor) so I have a fair amount of experience with people like your friend, who lack one or more of the critical elements to be successful but are stubborn about persisting because they are scared of feeling like failures. I think you might make some headway if you approach it from the lack of enjoyment standpoint. When he starts complaining, open up a dialogue about how he's feeling about his own creative process and whether he's getting real enjoyment out of what he's doing. Sometimes helping someone with a little perspective on their own frustrations is more productive than suggesting it's their talent that's the problem.